Circuit breaker



y 1941- 'r. G. A. SILLERS ET AL 2,251,171

- CIRCUIT BREAKER Filed Sept. 21, 1938 4 Sheets-Sheet l July r. s. A.SILLERS ET AL 2,251,171

CIRCUIT BREAKER Filed Sept. 21,, 1938 4 Sheets-Sheet 2 July 29, 1941.

T. G. A. SILLERS ET AL 2,251,171

"TTECUIT BREAKER I I Filed Sept. 21, 1958 4 Sheets-Sheg 3 July 29, 1941.T, s s ET AL 2,251,171

CIRCUIT BREAKER Filed Sept. 21, 1938 4 Sheets-Sheet 4- Patented July 29,194-1 CIRCUIT BREAKER Thomas G. A. Siilers, Wauwatosa, and AdolphErncstus, Milwaukee, Wis., assignors to Allis- Chalmcrs ManufacturingCompany, Milwaukee, Wis, a corporation of Delaware Application September21, 1938, Serial No. 230,922

15 Claims.

This invention relates in general to circuit makers and breakers and themechanism therefor and particularly to a circuit breaker having acontact biased to circuit opening position and an improved operatingmechanism for closing said contact and an improved means for trippingthe contact free of the closing mechanism.

In circuit breakers utilizing a direct motor drive for closing a contactagainst a heavy spring bias, utilized for opening the contacts, variousdisadvantages have been found. Reversing switches have been necessary toreverse the direction of the motor rotation in order to return theoperating mechanism to the original position ready for the nextsucceeding operation. Such operation required an almost instantaneousstopping of the motors exactly at closing position of the contact,thereby causing a shock to the operating mechanism due tov the stoppingimpact. The reversing operation was an additional operation afteropening of the breaker and necessitated. a switching operation in themotor control circuit. Slip clutches have been utilized to take up thestopping impact but these caused uncertain operation and considerablemaintenance.

In providing a trip free mechanism in an operating means of the abovetype, the tripping coil has been mounted on the moving element of theoperating mechanism. Such construction necessitates electricalconnection to the tripping coil through flexible leads which are subjectto crystallization and breakage due to the flexing.

It is therefore an object of the present invention to provide animproved circuit breaker and operating means therefor which avoids theabove disadvantages.

It is another object of the present invention to provide a circuitbreaker contact closing mechanism having a plurality of motors foroperating the mechanism.

It is another object of the present invention to provide a circuitbreaker operating mechanism which resets itself for an additionaloperation immediately upon closing of the contact.

It is another object of the present invention to provide in a circuitbreaker a motor operated contact closing mechanism in which the motorsrun in one direction only and slowly come to rest without load after thecontact is closed.

It is a further object of the present invention to provide in a circuitbreaker operating mechanism having fixed and movable parts, a means fortripping the contacts free of the closing mechanism, in which thetripping coil is mounted on a fixed rather than a movable member.

It is also an object of this invention to provide a circuit breakeroperating mechanism. that is.

simple and rugged in construction andoperation, low in first cost andmaintenance costs.

Objects and advantages other than those above set forth will be apparentfrom the following description when read in connection. with. the accompanying drawings, in which:

Fig. l is a diagrammatic view of" a circuit breaker and operatingmechanism therefor embodying the present invention. and: with theelements in the closed position;

Fig. 2 is a partial side view partly in section taken on the line IIIIof Fig. 1';

Fig. 3' is a diagrammatic view of the circuit breaker shown in Fig. 1but with the elements in. the tripped position;

Fig. 4 is a diagrammatic showing of the construction of. Fig. 1 butwith. the elements in. the

open position;

Fig. 5 is an end view of the gear assembly of the embodimentshown inFigs. 1-, 3 and-4;

Fig. 6 is a front. view of the gear assembly shown in Fig. 5;

Fig. '1 is a detailed view of the outer gear member of the assemblyshown, in Figs. 5 and 6;

Fig. 8 is a detailed view of the inner driven, member of the assemblyshown. in Figs..5 and: 6..

As shown generally in, Figs. '1, 3 and 4, a movable contact lllisbiasedto its open position relative to fixed contacts II by a spring l2. Inclosing the contact ID, the operative force is supplied.

by four motors l3. through a linkage of cranks and toggles. These motorssupply the closing force to the linkage through a gear assembly which isshown in detail in Figs. 5, 6, '7 and. 8. An outer gear 14 is driven bythe motors l3 which are spaced symmetrically thereabout. The

driving force of the gear I4 is transmitted to thelinkage by means of aprojection I6 on the gear M, which projection cooperates with aprojection H on an inner member I5 of the gear assembly. The membersHand 15 rotate relative .to each other on roller bearings l8 held inposition by retaining ring I4 bolted to gear M. The

motors I3 run in one direction only, therefore driving the gear It in acounterclockwise direction, as viewed in the drawings. The inner drivenmember I5 is free to rotate relative to the gear M in a counterclockwisedirection.

By utilizing a plurality of motors for supplying the closing torque,various advantages are obtained. The motors. may be spaced on the maindriving gear so that the closing torque is provided symmetrically aroundthedriving shaft, thus reducing tooth pressure on the gear and bearingwear on the main shaft. The driving force component against the mainshaft is balanced between the motors. In large installationsnecessitating a heavy closing mechanism of the type shown herein, theuse of a plurality of motors permits using small standard motors toobtain the necessary power. By using small motors, the starting inertiaof the motor element is easily kept low, while to accomplish this sameresult with one motor would require a machine having a very lengthysmall diameter rotor which would be dimcult to mount.

The use of a plurality of motors is additionally advantageous inproviding a standard circuit breaker operating mechanism which may beutilized on circuits having diiierent voltages. For example, if themotors are standard 110 volt motors, this drive arrangement can beutilized on 110, 220 or 440 volts merely by change of connection inseries, parallel, or series-parallel groupings. In any of the abovearrangements having two groups or more of motors in parallel, thefailure of one motor would not prevent the mechanism from beingoperative for the mechanism is designed to be sufiiciently powerful toclose with only one-half normal power provided. In such a case, theclosing time, of course, would be increased.

The mechanism as shown in Fig. i is in the contact open position withthe elements in normal position for performing the closing operation. Ifthe motors are energized, the gear 14 is driven in a counterclockwisedirection. The motors accelerate without load until the projection l6encounters the projection ii on the inner member i5. Rotation of themember i5 and the shaft it raises he link 23 in harmonic motion by meansof pin 2%. Raising of the link 23 pulls upwardly on pin 25 in the crank23 which is keyed to the lower driving shaft 27.

In the diagrammatic showing of the drawings, the motors l3, the gearassembly, link 23 and shaft 2? are shown displaced from their truepositions which are directly behind the toggle linkage and trippingmechanism. For the sake of clarity, these elements have been moved tothe left and the shaft 2? shown in perspective. The shaft ill extends ina plane perpendicular to the paper and rotates in a counterclockwisedirection to transmit the closing torque, as shown by the arrow, in Fig.i.

The rotation of lower shaft 27 rotates crank 28 which is keyed thereto,until pin 35 is against resetting stop 54. As this position of pin 35 isto the left of the center line between pin 3d and shaft 2'1, links 23and 38 form an over-center toggle. Rotation of crank 28 transmits anupward movement to saddle 29 by means of link 35 which is pinned to thecrank 28 and to the saddle by pins 35 and 34 respectively. The saddle isguide by rollers 30 between fixed points 33. In the absence of atripping operation, links 39, t0 and 43 move with the saddle 29 as onelink rotating the crank 3 about the fixed bearing poLnt in a clockwisedirection. Such movement of crank moves the contact it against the biasof the opening spring E2 to the closed position shown in Fig. 1.

It will be noted from the closed position shown in Fig. 1, that the pin26 is just at upper dead center and therefore the link 23 in itsuppermost position. The motors continue to rotate, under no load, and assoon as pin 2% is past upper center, the action of gravity on link 23and member l5 moves them to the position shown in pin 25 sliding in theslot 24.

This improved operating and resetting mecha nism provides manyadvantages. The motors l3 need run in one direction only, therebyeliminating need of reversing switches for resetting the operatingmechanism. The mechanism is reset for the next closing operationimmediately, rather than taking additional resetting time after thecircuit breaker has been opened. The motors (3 may be easily and simplycontrolled by limit switches for the necessity of instantaneouslystopping the motors i3 under the heavy closing load is avoided. Theclosing impact is not, therefore, suddenly transmitted through thelinkage to the operating gear.

The motors I 3 are allowed to slowly come to rest with the elements inthe position shown in Fig. 3 and a space is left between the cooperatingprojections l3 and H. At the start of the closing operation, the entirepower input to the motors can be utilized in acceleration of the motorsprior to cooperation of projections i6 and i'! to take up the closingload. As the member [5 is free to move in a counterclockwise directionrelative to the gear i i. any force transmitted through the linkage dueto tripping out of the breaker cannot be transmitted back to the gearteeth where such impact could do considerable damage. By avoidinginstantaneous stopping and reversal of parts, the resultant shock to theoperating parts is avoided. lhe closing force is supplied to the pin 25substantially in harmonic motion, thereby providing a high torque andlow speed during acceleration and deceleration of the closing mechanismand providing a high speed during the major portion of the closingstroke. Thus a high torque is supplied at the beginning of the strokewhich is desirable to overcome the inertia of the mechanism and toprovide the high torque desirable just as the contacts are being closed.Further during the major portion of the stroke a high speed is utilizedto lower the total time of the closing stroke. In other words, thegreater speed is obtained when the load is less, and the greater powerwhen the load is greater.

The tripping mechanism is so arranged that the contact i0 may be trippedfree of the operating mechanism at any time during the closing stroke.The link 39 has a hardened plate which bears against rollers 85 as shownin Figs. 1 and 2. The rollers $5 are mounted on pin 38 which is slidablein the slot 3! of the saddle 29. The angle of the plate :38 is so setrelative to the roller 65 that the link 39 tends at all times to movetoward the left as viewed in the drawings. Tripping movement of thislink 39 is restrained by a toggle composed of link 58 which is pinned tothe link 39 by pin 8i] and link H which is pinned to the saddle by pin34 and pinned to link 58 by pin 62. This toggle of links 53 and ll isheld in over-center position against an abutment of the saddle formingthe stop i 2.

When a tripping impulse is supplied to the coil 55, the core 5% thereofis moved upwardly and the trippin arm 5'! raises the tripping hammer 59to break the toggle between links 'H and 58. This action allows thecontact iii and the operating mechanism to move to the position shown inFig. 3. The link 48 has a slot 13 in which the pin 38 may move and link43 moves downwardly, the pin 33 sliding in the slot 3'! in the saddle.The shock of the movement of the link 39 to the left against the saddleis broken by the action of Fig. i, the

an extension 6! of the link 39- against a spring bumper 68. The actionof extension 61 on the bumper 68, which is mounted in the link 36, issuch that the pin is forced to the right of the center line between pin34 and shaft 21 and therefore the toggle between crank 28 and link 36 isbroken allowing the saddle 29 to drop. As the saddle 29 is quite heavy,a dashpot 69, acted upon by an extension 13 of the saddle, absorbs theimpact due to the downward movement.

It is noted that the tripping latch is mounted on a movable portion ofthe mechanism which allows the coil 55 to be mounted on a stationarypart of the mechanism. Stationary mounting of the coil permits solidelectrical connection thereto, thus avoiding the disadvantages offlexible cable leads for carrying current to moving elements. Byproviding the long tripping arm 57, the right hand end of which issubstantially fixed and the left hand end of which moves in an are aboutthe right hand end, the motion of the moving end is approximatelyequalized around the horizontal position of the arm. As the center,about which the tripping hammer 59 rotates, moves (when the saddlemoves) substantially on the circle of movement of the left hand end ofthe arm 51, the right hand end of arm 51 and hence the tripping coil 55,can be fixed.

Although but a single embodiment of the present invention has beenillustrated and described, it will be apparent to those skilled in theart that various changes and modifications may be made therein withoutdeparting from the spirit of the invention or from the scope of theappended claims.

It is claimed and desired Patent:

1. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, and means comprising a plurality of magneticallyindependent electric motors for moving said biased contact to circuitclosing position.

2. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, a shaft operably connected to said biased contact tomove the same to circuit closing position, and means for operating saidshaft comprising a plurality of magnetically independent electromotivedevices operatively connected to said shaft at points spacedsymmetrically thereabout.

3. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, and means having a low starting inertia for movingsaid biased contact to circuit closing position, said means comprising aplurality of magnetically independent electric motors.

4. The combination of a pair of contacts cooperable to make and break anelectric circuit and means for biasing one of said contacts to circuitopening position with means for operating said biased contact to circuitclosing position, said operating means comprising a rotatable member, aplurality of motors operatively connected to said member, at pointsuniformly spaced thereabout, a member driven by said rotatable member inone direction and free during said driving to move relative to saidrotatable member in said one direction, and a toggle mechanismoperatively connecting said driven member and said biased contactthrough a lost motion connection.

to secure by Letters 5'. In combination, a pair of contacts cooperableto make and break an electric circuit, means for biasing one of saidcontacts to circuit opening position, operating means provided withfixed and movable members cooperable to move said biased contact tocircuit closing position, said movable members comprising a togglelinkage and further comprising a saddle member guided in motion by saidiixed member, and means for tripping said biased contact free of saidoperating means during contact closing movement, said tripping meanscomprising cooperable latching members supported on said saddle member.

6. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, operating means provided with fixed and movablemembers cooperable to move said biased contact to circuit closingposition, said movable members comprising a toggle linkage and furthercomprising a saddle member guided in motion by said fixed member, andmeans for tripping said biased contact free of said operating meansduring contact closing movement, said ripping means including a solenoidmounted on said fixed member.

'7. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, operating means provided with fixed and movablemembers cooperable to move said biased contact to circuit closingposition, said movable members comprising a toggle linkage and furthercomprising a saddle member guided in motion by said fixed member, andmeans for tripping said biased contact to circuit opening positionindependently of movement of said saddle member.

8. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, means for operating said biased contact to circuitclosing position, said operating means comprising a driving member, adriven member and an operating connection therebetween whereby saiddriven member is rotated and guided by said driving member in onedirection and is free to rotate relative to said driving member butguided thereby in said one direction, means for tripping said biasedcontact to circuit opening position, and means for insuring movement ofsaid driving member through a predetermined cycle independently oftripping movement of said biased contact.

9. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, a linkage system connected to said biased contact andoperable to move the same to circuit closing position, means fortripping said biased contact free of said linkage system, means foractuating said linkage system comprising a motor operated memberrotatable in one direction only, and means comprising a pin and slotconnection between said motor operated member and said linkage systemfor operating said motor operated member through a predetermined contactclosing cycle independently of actuation of said tripping means.

10. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, a shaft operably connected to said biased contact tomove the same to circuit closing position, a motor operated memberrotatable in one direction only independently of movement of said biasedcontact, and means for operatively connecting said member and saidshaft, said means comprising a link provided with a pin and slotconnection.

11. The combination of a pair of contacts cooperable to make and breakan electric circuit and means for biasing one of said contacts tocircuit opening position, with means for operating said biased contactto circuit closing position, said operating means comprising a rotatabledriving member, a member driven by said rotatable driving member in onedirection and free during said driving to rotate relative to saidrotatable driving member in said one direction, a toggle mechanismoperatively connected to said biased contact, and means comprising alost motion operative connection between said driven member and saidtoggle mechanism whereby after said toggle is set said driven membercontinues rotation to initial contact closing position independently ofsaid driving member.

12. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, means for operating said biased contact to circuitclosing position, said operating means comprising a pair of membersconcentrically rotatable relative to each other, a pin and slotconnection between said biased contact and one of said members, and amotor for rotating the other of said members.

13. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, means for operating said biased contact to circuitclosing position, said operating means comprising a pair of membersconcentrically rotatable relative to each other, a pin and slotconnection between said biased contact and one of said members, and aplurality of motors connected to the other of said members atcircumferentially uniformly spaced points for rotation thereof.

14. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, means for operating said biased contact to circuitclosing position, said operating means comprising a pair of membersconcentrically rotatable relative to each other, a toggle linkageconnected to said biased contact, a pin and slot connection between saidtoggle linkage and one of said members, and a plurality of motorsconnected to the other of said members at circumferentially uniformlyspaced points for rotation thereof.

15. In combination, a pair of contacts cooperable to make and break anelectric circuit, means for biasing one of said contacts to circuitopening position, means for tripping said biased contact to circuitopening position either from circuit closing position or during closingmovement thereof, and means for operating said biased con tact tocircuit closing position, said means comprising a driving memberrotatable in one direction only through a predetermined contact closingcycle independently of operation of said tripping means and furthercomprising a driven member rotatable by said driving memberconcentrically therewith and guided thereby and provided with a lostmotion connection with said biased contact.

THOMAS G. A. SILLERS. ADOLPH ERNESTUS.

